A Florida grand jury has indicted Michael David Dunn on first-degree murder charges in the shooting death of Jordan Davis, an unarmed, black high school student, which occurred last month after an argument over loud rap music, Reuters reports.

Software developer Michael Dunn, 46, shot high school junior Jordan Davis, 17, through the window of a sport utility vehicle at a Jacksonville convenience store gas station on Nov. 23, before driving away, authorities say.

Dunn, who is white, faces charges of attempted first degree murder for firing at the car which contained three other passengers, all friends of Davis.

Dunn was arrested the day after the shooting for second degree murder and pleaded not guilty. He was being held in Duval County without bond awaiting arraignment.

The state attorney's office later decided to upgrade the charge to first degree murder, which in Florida requires a grand jury decision.

Dunn's arraignment on the new charges is scheduled for Dec. 17.

Davis's father, Ron Davis, has pledged to turn his son's shooting death into a crusade against guns and Florida's controversial Stand Your Ground law which allows people to defend themselves if they "reasonably believe" someone will hurt them …

Dunn's lawyer says he fired out of fear for his life when someone in the SUV brandished a shotgun and threatened him.